<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1,shrink-to-fit=no">
    <title>深入掌握CSS组件</title>
    <!--    Bootstrap核心css文件-->
    <link rel="stylesheet" href="https://cdn.bootcss.com/twitter-bootstrap/4.4.1/css/bootstrap.min.css">
</head>
<body class="container">
<h3 class="mb-4">设计配色</h3>
<nav class="navbar navbar-expand-md navbar-dark bg-dark">
    <a href="" class="navbar-brand mr-auto">Navbar</a>
    <form action="" class="form-inline">
        <form action="" class="form-inline">
            <input type="search" class="form-control mr-sm-2" placeholder="搜索">
            <button class="btn btn-outline-light my-2 my-sm-0" type="submit">搜索</button>
        </form>
    </form>
</nav>
<nav class="navbar navbar-expand-md navbar-dark bg-info my-2">
    <a href="" class="navbar-brand mr-auto">Navbar</a>
    <form action="" class="form-inline">
        <form action="" class="form-inline">
            <input type="search" class="form-control mr-sm-2" placeholder="搜索">
            <button class="btn btn-outline-light my-2 my-sm-0" type="submit">搜索</button>
        </form>
    </form>
</nav>
<nav class="navbar navbar-expand-md navbar-dark" style="background-color: #e3f3fd">
    <a href="" class="navbar-brand mr-auto">Navbar</a>
    <form action="" class="form-inline">
        <form action="" class="form-inline">
            <input type="search" class="form-control mr-sm-2" placeholder="搜索">
            <button class="btn btn-outline-success my-2 my-sm-0" type="submit">搜索</button>
        </form>
    </form>
</nav>




<!--引入js文件-->
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.6/umd/popper.min.js"></script>
<!--Bootstrap核心JavaScript文件-->
<script src="https://cdn.bootcss.com/twitter-bootstrap/4.4.1/js/bootstrap.min.js"></script>
</body>
</html>